package com.infra.micro.quartz.domain.core;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.DisposableBean;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.stereotype.Component;

/**
 *  获取spring上下文
 */
@Component
public class SpringContextBean  implements ApplicationContextAware, DisposableBean {

    private static final Logger LOGGER = LoggerFactory.getLogger(SpringContextBean.class);

    private static ApplicationContext applicationContext = null;

    /**
     * 从静态变量applicationContext中取得Bean, 自动转型为所赋值对象的类型.
     */
    @SuppressWarnings("unchecked")
    public static <T> T getBean(String name) {
        assertContextInjected();
        return (T) applicationContext.getBean(name);
    }

    /**
     * 从静态变量applicationContext中取得Bean, 自动转型为所赋值对象的类型.
     */
    public static <T> T getBean(Class<T> requiredType) {
        assertContextInjected();
        return applicationContext.getBean(requiredType);
    }

    /**
     * 检查ApplicationContext不为空.
     */
    private static void assertContextInjected() {
        if (applicationContext == null) {
            throw new IllegalStateException("applicaitonContext属性未注入, 请在applicationContext" +
                    ".xml中定义SpringContextHolder或在SpringBoot启动类中注册SpringContextHolder.");
        }
    }

    /**
     * 清除SpringContextHolder中的ApplicationContext为Null.
     */
    private static void clearHolder() {
        LOGGER.debug("清除SpringContextHolder中的ApplicationContext:"
                + applicationContext);
        applicationContext = null;
    }

    @Override
    public void destroy() {
        SpringContextBean.clearHolder();
    }

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        if (SpringContextBean.applicationContext != null) {
            LOGGER.info("SpringContextHolder中的ApplicationContext被覆盖, 原有ApplicationContext为:" + SpringContextBean.applicationContext);
        }
        SpringContextBean.applicationContext = applicationContext;
    }
}